code: def _cast_all_to_dtype(values, dtype):
      return [tf.cast(v, dtype) for v in values]
  
imports: import numpy
  import scipy.sparse
  import tensorflow
  from spektral.data.utils import to_disjoint
  from spektral.layers import ops
  from spektral.utils import convolution
  from spektral.utils.sparse import sp_batch_to_sp_tensor, sp_matrix_to_sp_tensor
label_desc: Use image node_id 3 for calling a global function with example usage: _cast_all_to_dtype(values, dtype) and returns: unknown